Advertisement

Advertisement

BIG PHYSICS, BIG QUESTIONS –

Science: Albatrosses break speed and distance records

ALBATROSSES, the largest flying seabirds, could have evolved only in
the southern oceans, say ecologists in France. This is because the birds
rely heavily on wind assistance to make their long foraging trips, and the
‘bottom’ of the world is the only place where winds blow incessantly.

Pierre Jouventin and Henri Weimerskirch of the National Centre for Scientific
Research at Beauvoir have tracked six foraging albatrosses by satellite
and discovered just how far the birds travel. This is the first time anyone
has succeeded in tracking wild birds in this way (Nature, vol 343, p 746).

Jouventin and Weimerskirch fitted the wandering albatrosses (Diomedea
exulans) with radio transmitters weighing only 180 grams. The males went
to sea for as long as 33 days while their partners remained at home to incubate
the eggs.

The researchers tracked the albatrosses by satellite as they moved across
the south-western Indian Ocean. They found that in a single feeding trip
the birds covered between 3600 and 15 000 kilometres.

Advertisement

According to the French biologists, the birds broke all the records.
‘Both the distances covered and the long-distance flight speeds were much
higher than the highest estimates for this or any other species of bird.’
The birds easily maintained a speed of 56 kilometres an hour over a distance
of more than 800 kilometres.

The albatrosses accomplished these feats of speed and endurance, say
the researchers, by making the most of prevailing weather conditions. On
the outward journey, they exploited the winds; on the return, they tacked
in to their home island to avoid facing into the wind. They looped around
or flew a zigzag course until they found favourable winds.

Jouventin and Weimerskirch say that when the birds are incubating their
eggs in the spring, their foraging partners may be trapped in a rare high-pressure
system for as long as a week. But albatrosses are very patient creatures:
back at the nest, the partner will fast for as long as 50 days before abandoning
the egg.